Adrial:

It all has to come out. The studs can stay.

There are three oil galley plugs. One front, rear and near #1 perpendicular to the crank. You can find it from underneath. Do not remove this one, unless you can find a part # for it. I spoke with four different dealers and some independents, and struck out. It is necessary to remove the front and rear ones, but optional on this one. You can get a brush in the hole from the head side to clean the vertical oil galley. This is the feed for the cam and lifters. Drill a hole in the middle of the front and rear ones, carefully heat the block around them and knock them out. I knock in one side and grab the other with vice grips and wiggle them out.

I do not agree with having to align bore the mains. This is very common with american iron, but I have not found any main bearings that will accomodate this procedure on our engines. It opens up a whole new can of worms and creates the need for unobtanium parts. This is just my opinion from my limited experience. I am not in the Porsche engine rebuilding business, have kicked it around some though. There is a local machine shop that has the Sunnen machine and can do the special bore polishing, but they want me to buy the pads and stones. Anyway, I ramble.

Some random thoughts.
When installing the crank, have an assistant carefully apply rearward pressure to the crank with a "very clean" pry bar to seat the thrust bearing while you are torquing the big ones. You could also use a block of wood, and give it some alternating taps front and rear. If you stand is like mine, access to the flywheel end is very limited. I put the nuts on finger tight, and rock the crank back and forth first to get the thrust bearings squared up. It will not move much. The technical spec booklet has the order for torquing the nuts. Bascially, you start in the middle and go in a circle. I can copy it an post for you if you need. The big nuts are torqued to a starting value and then turned twice 60 degrees. I let the engine relax for at least twenty minutes between torquing sessions.

This reminds me of a basic rule often forgotten. Clean your tools prior to beginning reassembly. They will be nasty from the disassembly. Cleanliness is crucial to a good job. Use assembly lube on all the bearings and parts that rub together except the rings and cylinder walls. If you have the forged rods, have ARP or Raceware rod bolts installed and have the big ends resized. Rod bolts cost around $140 for a set, plus installation. Balancing the crank, rods and pistons is also a good idea. There is almost no place to stop if you are doing a race motor, but street engines do not need "everything". You have to decide how far to go and where to stop.

The nitpicky details are the hard part.

 

Damn you guys!!!! I just talked to Anderson Motorworks briefly and I'm now having 2nd thoughts about pulling the crank. I'm even thinking about having the crank lightened while i'm in there. Doh!!! I swear these motors are an endless pit of money.

 

Like you said 'Bankruptcy is temporary, Fun is Forever'

 

Thanks guys for all the help! It's much appreciated.

I have a few questions still.

The studs holding the crank girdle, do they stretch like the headstuds? Do they at any point need to be replaced? Do I need to worry about the number of times that I torque the crank girdle?

I looked up the specs for the wear limits for out of round cylinder bores. It is listed as .020 for the wear limit and .010 for new. It doesn't list the units however, I assumed it was in mm. This translates to .000787 inches. The bore measuring tool I have is accurate to the thousanths...am I mis-interpreting the factory manuals or is the tool just not accurate enough?

I have started to research machine shops in the area to take the block/crank/etc... to to be measured. Will also have the block checked to be sure its flat.

If it isn't too costly, I will have all rotating parts balanced. The head I will have a standard rebuild done, maybe a little fancy work but nothing crazy $$ wise.

The crank I will get cross drilled and balanced by Lindsey most likely.

Looking at my plan as it stands now, I dont expect it to be very expensive. Granite, what am I missing? You said you expect to spend $2800 on your rebuild...on what?

$500 max on headwork, $300 on the crank, $100-$200 to have everything measured by the machine shop, $100 rings, $100 main bearings, $300 all gaskets, $250 raceware head studs....what am I missing in the list?

I posted pics of the condition of the cylinder walls, HG and head in an earlier thread, they can be seen here: http://www.eden.rutgers.edu/~adrialk/rebuild

thanks again,
Adrial

 

I agree that one needs to set goals and know what to do and when to stop.

On the balancing however, I think unless you balance ALL of the rotating and reciprocating parts, it's a waste of money to balance ANY of them. A job 90% done is still a job undone. The flywheel, pressure plate, crank, and crank pulley should be balanced separately and as a complete unit. Anything less is a waste of money IMHO.

 

I would be surprised if they do not have a stretch limit. Look in the FSM for this (I sure hope you are not attempting this w/o one).

Ah yes, that makes sense. At first was thinking inches, and though "man the 944 engine is a sloppy one." But, mm makes sense. Yes, your tool does not have enough resolution. My Sentra SE-R engine had tolerances to the ten thousandth. Bore gauges with that accuracy are very very pricey. Then, you need to have good experience with them before I'd trust your measurements since technique could affect the accuracy at those levels.

 

I do have the FSM and will check for stretch limits on the crank girdle studs.

Here's my general layout...
How much more money should I allot to the balancing of rotating masses?



Rod bearings are missing from the list because I already have them.

 

Off the top of my head it looks pretty reasonable to me. I have not done a 944 engine yet, so I cannot tell if anything is missing. I would always plan on a couple hundred for miscellaneous things that come up.

 

Adrial, sorry about the format of this list. All of the machine shop work I will be having done, the parts list is a partial, and only my estimates at this time. I have already had my engine (actually 2 engines and heads and camshaft/housings) into the machine shop, mic'd out and this is what will be required to rebuild either one of the engines I took in. Note: both of these engines had blown the timing belt. One with approx. 140k on it, the other, 171k. Most the bores were eggshaped and over max. spec. by a min. of .007". Do hope yours are much better! Your pistons would cost as much for one piston, as I already paid for all 4 oversized. My plan is to hopefully get engine into the machine shop within the next 2 months. Maybe this will help with ideas of some of the possible things/costs.



Machine Shop (quoted estimate)
______________________________________

Bore cylinders (4) 300.00
Hone main line 75.00
Cleaning Head and block 90.00
Flywheel resurface 48.00
Head (resurface) 60.00
Block (resurface) 90.00
Rods (rebore) 105.00
Rods (rebush and pin fit) 95.00
Rods/piston assembled&aligned 45.00
Valve Grind 175.00
Valve Guides R&R 96.00
Valve seat installed (1) 60.00
Valve stem Ht. Adjustment 25.00
Welding Alluminum (on head, corrosion pockets & misc.) 75.00
Crankshaft Polish 50.00
_________
1389.00


ADDITIONAL PARTS NEEDED: (all estimates, parts yet to be bought)
_______________________________________________________

ARP rod bolts/nut kit 145.00
Complete engine gasket kit (german made) 400.00

Exhaust Valves (4each) (TRW) 140.00

Valve Guides/seals (all 8 ) 54.00
Waterpump (new) 200.00
Thermostat 12.00
Timing/balance/rollers Kit
130.00

Piston Kits ( OS, 4 total) Mahle (already purchased)
450.00
Head Bolt Kit 50.00
Tune up Kit 100.00
Rod Bearings 50.00
Main Bearings

140.00
Cam Followers (set of 8) 350.00
___________
2221.00
1389.00 + 2221.00 = $3610.00

 

Whoa, only $300 for all 4 pistons to have them bored?? Is that including the special coating? (alusil I think it is?)

Also, you said they were out of round by .007 inches? Wow! Considering that the wear spec in the factory service manuals is .000787 inches.

 

Wear limit is more like .003" from new, at least on mine (M44/7). Yeah, plenty bad enough, but most looked pretty darn good just looking at them.
You could barely feel anything that resembled a ridgeline on them. Its not a coating, but a honing process that brings the silicates in the alluminum to the surface after boring them.Yeah, $300.00 I thought was pretty good (this was quoted a few months back), and this shop does a fair amount of these engines, including for the local racers. (if I don't get it in for them to work on here in the next couple of months, their schedule will be full doing all the racers stuff again).But if you price out OS pistons in a Mahle, you'll die! (especially for a turbo).I bought my piston kits some time ago when I first started thinking about this. I do believe I got one set of about the last 3 complete sets that were available for this price. My understanding is that the price for these on new stock has just about doubled. If you do need a rebore, you'll probably be alot better off going with a sleeved block and JE pistons for the costs involved with a turbo. I'm surprised a lot of others on the board haven't chimed in with their rebuild costs yet, the ones that have already done it, and spent the money. good luck!

 

Looking at the other measurements, it appears they are in mm. So I would assume that the cylinder bores are also in mm, which leads me to the .000787 inches number. Can anybody explain?

thanks

 

I'm not sure what you want explained. If it's a sanity check, I say it makes sense. Just for a point of reference to show that other aluminum engines are built to similar tolerances, the Nissan SR20DE engine I built has cylinder bore out of round tolerance of 0.0006". Yep. Six ten thousandths.

Some of this is simply due to thermal expansion of aluminum. Iron blocks don't expand as much and can be sloppier. The championship winning Nissan GTP engines were an interference fit at room temperature! They had to be assembled in a warm oil bath and could not be started until hot oil had been pumped through them for several minutes.

 

Well, using my bore measuring tool that reads in .0005 inches, I get something around .0008 or so...so its not "obviously OK" and needs to get professional measured. Also this confirms that the numbers in the factory manuals are definetely in mm. Tight tolerances! (they seem like it to me anyway).

 

Indeed they are. Look at the piston to bore clearances. That's pretty damned tight.

As for your bore out of round, I wonder if anyone has a torque plate for the 944? A friend of mine built an engine just list mine and with the torque plate off, the bore was out of round by an amount greater than the FSM tolerance and greater than the piston to bore clearance!